The technology presented herein relates to a camera module comprising an optical structure capable of adjusting the focal point of a lens, a manufacturing method of such a camera module, an electronic apparatus incorporating such a camera module, and a manufacturing method of an electronic apparatus incorporating such a camera module.
As conventional camera modules, there is a camera module produced by combining an optical structure including a lens with a solid-state image pickup device (see, for example, Japanese Patent Application Laid Open No. 11-295576 (1999)). Moreover, an image module (camera module) with an auto-focus function capable of adjusting the focal point of a lens was proposed (see, for example, Japanese Patent Application Laid Open No. 2003-75712).
An electronic image pickup apparatus (conventional example 1) disclosed in Japanese Patent Application Laid Open No. 11-295576 (1999) is an electronic image pickup apparatus (camera module) comprising a solid-state image pickup device and a lens assembly which are coaxially disposed so that the solid-state image pickup device is positioned inside the lens assembly on a wiring board. In the electronic image pickup apparatus of conventional example 1, a locking part is formed on the outer periphery of the case of the solid-state image pickup device, a pawl part is formed on the mount (lens assembly), and the lens assembly is attached to the solid-state image pickup device by engaging the locking part and the pawl part. In the conventional example 1, since the locking part is formed on the outer periphery of the case of the solid-state image pickup device, there is a limitation on the outer shape of the case, and there is a problem in terms of reduction of the size of the electronic image pickup apparatus (camera module). Moreover, since a substrate for connecting circuit components other than the solid-state image pickup device is additionally required, there is a problem that the number of parts increases. Further, since the engagement position is limited to the outer periphery of the case and the edge of the mount, there is a problem that sufficient engagement cannot be ensured.
FIG. 1 is a perspective cross sectional view of a conventional image module with an auto-focus function. This conventional image module with an auto-focus function (conventional example 2) is a camera module disclosed in Japanese Patent Application Laid Open No. 2003-75712, and composed mainly of an image packaging (package with a solid-state image pickup device mounted therein) and a lens blade unit (optical structure). The image packaging comprises a sensor 111, a substrate 112, a sensor cover 113, and a sensor filter 114. The sensor 111 performs the function of sensing image data. The sensor 111 is disposed on the substrate 112, the sensor cover 113 externally covers the sensor 111 and the substrate 112, and the sensor filter 114 only passes light between the sensor cover 113 and the sensor 111 and shuts out the external environment.
The lens blade unit performs the function of an actuator, and comprises elastic means 116 to which a current is supplied from outside, a coil 119 wound so that an induced current flows from the elastic means 116, a magnet 120 disposed so that an electromagnetic field is formed by the current flowing in the coil 119, a lens blade 118 that receives the electromagnetic force generated by the coil 119 and magnet 120 at the upper and lower sides, and a lens 117 which is connected to the middle of the lens blade 118 and moves up and down. Moreover, the lens blade unit has a holder 15 positioned outside the sensor cover 113 to support the elastic means 116.
In the conventional example 2, since it is necessary to additionally connect a lead wire to the elastic means 116 which also functions as a terminal of the coil 119, there are problems that the assembly process is complicated and the number of parts increases. Moreover, there are problems that it is not easy to connect the image packaging and the lens blade unit, it is difficult to separate the image packaging and the lens blade unit from each other if they are connected once, and, if one of them has a defect, both of them are treated as defective. Further, in the case where the optical structure and the device substrate are bonded together, it is necessary to wash the bonding surface of the optical structure and it is necessary to apply heat to harden an adhesive, thereby causing bad influences on the optical structure.
As described above, the camera module of conventional example 1 has a limitation in terms of reduction of the size because the case in which the solid-state image pickup device is mounted is engaged with the lens assembly, and also has a problem that the number of parts increases. Moreover, this camera module has a problem that sufficient engagement cannot be ensured. On the other hand, the camera module of conventional example 2 suffers from problems that the connection of the coil terminal for auto-focus is complicated, and the number of parts increases. Further, this camera module has problems that it is difficult to separate the image packaging and the lens blade unit from each other, and it is not easy to reduce the cost because an increase in the cost due to defective products cannot be avoided. Besides, in the case where the optical structure and the device substrate are bonded together with a thermosetting adhesive, there is a problem that the optical structure is affected by the washing of its surface and heat in the thermosetting process.